Brush strip



July 2, 1957 J, BENYAK 2,797,425

BRUSH STRIP Filed Oct. 5. 1954 'INVENTOR.

10/! 5. BfIVY/IK TOR/V575.

conditions of use.

United States Patent M BRUSH STRIP John B. Benyak, Cleveland, Ohio, assignor to The Osborn Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application October '5, 1954, Serial No. 460,306 9 Claims. C1. 15-132 This invention relates as indicated to novel brush strip, and more particularly to flexible brush strip adapted for circularization about a relatively small radius in the manufacture of rotary brush elements and the like.

Brush strip comprising an elongated sheet metal channelform back in which brush bristle material is retained by means of an elongated retaining element or wire extending longitudinally therein is a well-known article of commerce and is produced in very large quantity. When designed for employment in high speed rotary brushes and therefore subjected to considerable centrifugal force in use, it was early appreciated that some means should be provided more firmly to secure the wire retaining element within the channel, and Bickel Patent 1,963,045 discloses a form of brush strip having teeth turned in from the channel edges to overlie the wire. Such brush strip has enjoyed considerable commercial success and is manufactured at the present time for use in certain types 0f brushes. There has been an increasing tendency to operate power driven rotary brushes at greater and greater speeds and to subject them to increasingly severe Peterson Patent 2,303,386 discloses a considerably improved form of brush strip wherein teeth of a particular configuration are punched in from the brush strip channel sides at points appreciably spaced from the channel edges. Among other advantages, it has been found that such brush strip may be circularized into annular or helical form with greatly reduced likelihood -of tearing of the channel edges which are, of course, ,greatly tensioned and stretched by such circulariza'tion operation. Nelson Patent 2,609,242 discloses yet another form of tooth bearing brush strip wherein the teeth protrude from an inner element or inner elements secured within the channelform back, as by spot welding for example. This construction affords a channel back, the outer sides of which are unbroken and accordingly capable of stretching during circularization without the localized concentrations of stress and resultant tearing which may occur when the channel sides have openings punched therein. Brush strip as disclosed and claimed in Nelson Patent 2,609,242 has pro-yen particularly satisfactory when it has been desiredto bend or circularize the strip about a very small radius. The mode of manufacture, however, is obviously relatively expensive as compared to that of Peterson Patent 2,303,386, and accordinglyit is not ordinarily employed exceptwhen it has been found absolutely necessary to 'do'so.

It is accordingly a principal object of my invention to provide an improved form of brush strip which will be relatively inexpensive of manufacture but adapted for circularization about a small radius without danger of tearing the edges of the channelform-back within which the brush material is retained.

Another object is to provide such brush strip utilizing transverse teeth -to secure an elongated retaining element within 'thechannelfor'm back, such teeth being secured to 'the channel 'back in a manner avoiding localized con- Patented July 2, 1957 '2 centrations of stress therein when the brush strip is bent or circularized.

Still another object is to provide such method of manufacture which will lend itself to continuous automatic operation.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

Fig. 1 is a top plan view of a portion of a preformed sheet metal strip adapted for use in the manufacture of my new brush strip;

Fig. 2 is aperspective view of the preformed strip of Fig. 1;

Figs. 36 inclusive illustrate successive stages in the manufacture of such preformed metal strip;

Figs. 7 and 8 show the subsequent employment of the preformed backing strip in the manufacture of brush strip;

Fig. 9 is a diagrammatic perspective view illustrating the operations shown in section in Figs. 7 and 8;

Fig. '10 shows a rotary brush element formed of circularized brush strip in accordance with my invention; and

Fig. 11 is an enlarged transverse cross-section through my new brush strip illustrating the construction thereof.

Referring now more particularly to said drawing, a continuous length of thin steel strip or tape 1 may be withdrawn from a coil thereof and passed through a punch press to punch out 'tWo parallel rows of teeth 2 and 3 adjacent the respective edges thereof, such teeth lying in planes transversely of the strip and being shaped in the manner taught in Peterson Patent 2,303,386 except that the longer straight edges parallel to the edges of the strip 1 comprise the inner edges of such teeth. As shown in Figs. 4-6 inclusive, the continuously traveling strip passes through a series of forming rolls which flange up the respective tooth bearing edge portions of the metal tape and fold the same over against the inner body of the tape so that the teeth now protrude in the opposite direction and the tape in transverse crosssection is of single thickness in its longitudinally extending central portion but of double thickness in its two side edge portions. Moreover, the beveled edges of the teeth 2 and 3 which originally were directed outwardly are now directed inwardly toward one another.

The finished brush strip may now be formed in the same general manner described in the aforesaid Peterson Patent 2,303,386 and diagrammatically illustrated in Figs. 79 inclusive of the present application. The brush bristle material 6 is disposed transversely of the metal tape 1 and awire retaining element 7 is laid thereon along the longitudinal center line of the tape. This assembly is then passed between appropriate forming rolls to shape the tape to channel form with the brush material doubled about the wire and the wire secured beneath the transversely extending teeth 2 and 3. Referring now more especially to Fig. 11 of the drawing which shows the completed brush strip in enlarged cross-section, it will be seen that the outer side walls 8 and 9 of the channelform back are imperforate, and accordingly there are no regions tending to develop concentrationsof stress when the brush strip is subsequently deformed as by circularization to form the helically wound brush element of Fig. 10 where the brush bristles extend generally radially outwardly from the channelform back 10. The inturned folded portions 11 and 12 which carry the teeth 2 and 3 are, of course, continuously integral with the respective channel sides 8 and 9 along the outer edges 13 and 14 of the latter so that such teeth are very firmly supported in their function of securing wire 7. It will be obvious that when the brush strip of Figs. 8, 9 and ll is circularized as shown in Fig. 10 the transversely projecting teeth 2 and 3 will lie in radial planes including the axis of such circularized brush. Such edge portions 13 and 14 are, moreover, smooth and rounded as well as being reinforced by the double thickness of the material. It is accordingly possible to employ somewhat thinner gauge metal tape in the manufacture of the channel back than would otherwise be feasible.

In typical brush strip produced in accordance with my invention, steel tape having a thickness of .015 inch and a width of A; inch may be employed. Depending upon the particular operating conditions to be met, various other materials may be selected as desired, including copper, brass, aluminum, and stainless steel. Similarly, any desired brush material may be utilized including crimped wire, nylon coated wire, nylon monofilaments, tampico fiber, and horsehair. As above indicated, my new brush strip is particularly designed for circularization in the production of annular rotary brush elements such as that illustrated in Fig. 10, for example, and may be thus employed in the formation of single turn annular brush sections or helically wound elements having a brushing face of substantial width. elements may be mounted upon a variety of appropriate hubs or directly upon a mandrel or arbor as described in Peterson Patents 2,316,185 and 2,609,559, for example.

As shown in the drawing, the teeth extending from one side of the channel will desirably be nearly long enough to reach the far side whereas the other teeth are barely long enough to extend over and secure the retaining Wire. This minimizes shearing of the bristles but ensures that at least one set of teeth will still overlie the wire even if the channel later tends to open out somewhat.

In the past, the bristles have tended to bulge through the apertures in the channel sides formed when the teeth are punched and since these apertures may have rather sharp inner edges a certain amount of cutting of the bristles resulted. With my new construction, however, relatively thin tape may now be employed in the manufacture of the same size brush strip and the apertures in the folded portions are backed by the unbroken channel sides so that there is very little room for the bristles to bulge and cutting and shedding of bristles from this cause is substantially eliminated.

When the brush strip is circularized, unless the chantie] is appreciably necked in, the inner folded edge portions tend to swing toward the wire due to the tension imposed but this movement is of course prevented by the dense fill of brush bristles secured in the channel back. Nevertheless, such tendency causes the inner edges of the folded portions forcibly to press against the bristles and enhance the grip by which such bristles are held against withdrawal from the brush in use.

My invention is of particular advantage when employing teeth formed by punching as above explained, but such teeth may be formed in various other ways if desired, as by forming dimples with corresponding protuberances or by welding teeth to the inturned folded edge portions. The teeth may be slightly longitudinally offset so that while the shorter teeth project toward the solid metal of the opposite channel side wall the longer teeth project toward the apertures in the opposite inturned edge portions, permitting squeezing of the channel back to a slightly narrower transverse dimension.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any Such brush n iii 4. of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A rotary brush element comprising a circularized length of brush strip having a radially outwardly opening sheet metal channelform back with imperforate outer side walls, inturned channel lip portions folded against the inner faces of said side walls, teeth punched up from said inturned portions extending normal thereto and transversely of said channelform back, a wire retaining element disposed beneath said teeth longitudinally of such channel, and brush material doubled about said wire and secured in said back thereby with such brush material protruding from the channel mouth.

2. A rotary brush element comprising a circularizcd length of brush strip having a radially outwardly opening sheet metal channelform back with imperforate outer side walls, inturned channel lip portions folded against the inner faces of said side walls, teeth projecting generally at right angles from said inturned portions and extending transversely of said channelform back, a wire retaining element disposed beneath said teeth longitudinally of such channel, and brush material doubled about said wire and secured in said back thereby with such brush material protruding from the channel mouth.

3. A rotary brush element comprising a circularized length of brush strip having a radially outwardly opening sheet metal channelform back with imperforate outer side walls, inturned channel lip portions folded against the inner faces of said side walls but spaced substantially from the channel bottom, teeth projecting from said inturned portions extending transversely of said channelform back, a wire retaining element disposed beneath said teeth longitudinally of such channel, and brush material doubled about said wire and secured in said back thereby with such brush material protruding from the channel mouth.

4. A rotary brush element comprising a eircularized length of brush strip having a radially outwardly opening sheet metal channelform back with imperforate outer side walls, inturned channel lip portions folded against the inner faces of said side walls but spaced substantially from the channel bottom, teeth punched up from said inturned portions extending transversely of said channelform back and leaving corresponding apertures in said inturned portions, said teeth lying in planes radial of said circularized element and the radially outer edges of such apertures being parallel to the folded channel edges, :1 wire retaining element disposed beneath said teeth longitudinally of the channel, and brush material doubled about said wire and secured in said back thereby with said brush material protruding generally radially outwardly from the channel mouth.

5. The brush element of claim 4 wherein said teeth projecting from one side are appreciably longer than the teeth projecting from the other side.

6. Brush strip suitable for circularization to form a rotary brush element comprising a sheet metal channelform back with imperforate outer side walls, inturned channel lip portions folded against the inner faces of said side walls, teeth punched up from said inturned portions extending transversely of said channelform back, a wire retaining element disposed beneath said teeth longitudinally of such channel, and brush material doubled about said wire and secured in said back thereby with such brush material protruding from the channel mouth.

7. Brush strip in accordance with claim 6 wherein said inturned portions are spaced substantially from the channel bottom.

8. Brush strip comprising an elongated channel back on selfsupporting sheet material having imperforate outer side walls, inturned channel lip portions folded against the inner faces of said side walls, teeth projecting from said inturned portions extending transversely of such channel, an elongated retaining element disposed beneath said teeth longitudinally of such channel, and brush material secured in said back by said retaining element With said brush material protruding from the channel mouth.

9. A rotary brush element comprising a. circularized length of brush strip having a radally outwardly opening sheet metal channelform back With imperforate outer side Walls, inturned channel lip portions folded against the inner faces of said side walls but spaced substantially from the channel bottom, teeth projecting from said inturned portions extending transversely of said channelform back, a Wire retaining element disposed be- 6 neath said teeth longitudinally of such channel, and brush material doubled about said Wire and secured in said back thereby with such brush material protruding from the channel mouth, said transversely projecting teeth being flat and lying in radial planes including the axis of said circularized element.

References Cited in the file of this patent UNITED STATES PATENTS 1,869,102 Herold July 26, 1932 2,296,922 Gross Sept. 29, 1942 2,609,242 Nelson Sept. 2, 1952 

